Ground Track Control Using Differential Drag for Small Earth Observation Satellite Constellations

Abstract

This paper presents a framework for the acquisition and the maintenance of ground track configurations of small Earth observation satellite constellations. Specifically, the relative ground track spacings at the equator are controlled using differential drag to achieve the desired Earth coverage pattern without a propulsion system. The proposed framework is based on a divide-and-conquer approach to solving the optimal differential drag constellation management problem and comprises five processes for solving the related subproblems. The proposed framework can be used to manage end-to-end applications, from establishing the initial acquisition plan for the target ground track configuration, to the closed-loop command generation for the ground track acquisition and maintenance. Using the proposed framework, optimal acquisition plans with the minimum time and minimum altitude losses can be identified in a systematic way. The usefulness of the proposed method is demonstrated based on simulations incorporating the uncertainties in drag prediction.